Bigger engine on Mighty Mac
Given the high praise I have read on this forum for the Mighty Mac 12PT, I have been searching for one for the last few months. I just brought one home for a mere $100. It is in good shape, although it is missing the baffle door where the material exits the machine and the shield in the shredder hopper that keeps material from blowing back out. I ordered those parts from Mackissic and they emailed the manual (man they do customer service right).
The reason it went so cheap is the engine. The original engine died. It was replaced with a used 8hp Briggs from who knows what. It runs terrible because the float in the carb is broken (leaking gas and surging). Plus it has no throttle control. These are things I can fix but I would like to put a Honda engine on it eventually. So I have been looking for a replacement engine and found a used GX390 (13HP and 18.50 ft/lbs. of torque).
So here is my question. How much power can these machines handle. Mackissic now uses a Briggs with 11.5 ft/lbs. of torque on the residential version (and 13.5 on the commercial version). I talked to a tech at Mackissic and he suggested the GX240 (7HP, 11ft/lbs.) or GX270 (8hp, 13ft/lbs.), which seems conservative. But what do I know; mine is running so terrible I cannot tell if it is the leaves bogging it down or its just choking on gas.
Bottom line, what is the biggest engine someone has safely put on this machine?